Spindle tip extension for spinning with a reduced balloon

ABSTRACT

The spindle tip extension is sized so that the length of the shaft between the spindle tip and the transition of the crown cone to the shaft is one-half times to three times longer than the shaft diameter and the crown length between the point of maximum crown diameter and the transition of the crown cone to the shaft is 1 1/2 to 4 times more than the length of the shaft, while the crown cone forms an angle of 8* to 13* with the axis of rotation of the spindle.

United States Patent 1191 111 3,726,076 Wiirmli 14 1 Apr. 10, 1973 [54] SPINDLE TIP EXTENSION FOR 2,217,371 10 1940 Kowan'ck ..57 73 SPINNING WITH A REDUC 2,622,388 12/1952 Roeder 1 ..57 73 BALLOON 3,070,325 12/1962 Porter ..57/73 [75] Inventor: Arthur Wiirmli, Winterthur, Swit- FOREIGN PATENTS OR APPLICATIONS l Zefland 634,935 1 H1963 Belgium ..57/73 [73] Assignee: Rieter Machine Works, Ltd., Win- 704,037 2/1954 Great Britain v ..57/73 terthur, Switzerland 1,034,456 6/ 1966 Great Britain ..57/73 [22] Filed: Nov. 19, 1970 Appl. No.: 91,012

Primary Examiner-John Petrakes Atlorney Kenyon & Kenyon Reilly Carr & Chapin [5 7 1 ABSTRACT The spindle tip extension is sized so that the length of the shaft between the spindle tip and the transition of the crown cone to the shaft is one-half times to three times longer than the shaft diameter and the crown length between the point of maximum crown diameter and the transition of the crown cone to the shaft is 1 /2 to 4 times more than the length of the shaft, while the crown cone forms an angle of 8 to 13 with the axis of rotation of the spindle.

24 Claims, 9 Drawing Figures PATENTEBAPR 1 01973 SHEET 3 BF 3 Fig. 9

INVENTOR.

SPINDLE TIP EXTENSION FOR SPINNING WITH A REDUCED BALLOON This invention relates to a spindle tip extension. More particularly, this invention relates to a spindle tip extension for spinning with a reduced balloon.

I-Ieretofore, various types of spindle tip extensions have been known for use on ring spinning and ring twisting-machines. For example, tip extensions have been known to include a thread carrying crown provided with groove-like recesses and a shaft which has connected the extension to a spindle. The diameter of the shaft has been smaller than the diameter of the crown and less than one third of the spindle diameter. In addition, the crown has been tapered conically towards the spindle. In some cases, in order to form a reduced thread balloon with only a few wraps of the thread around the shaft, the diameter of the shaft has been held to less than one third of the spindle diameter, the surface of the step between the shaft and the spindle has been inclined 45 to 90 towards the spindle and the thread carrying crown diameter has been made two to five times larger than the shaft diameter. However, this spindle tip extension has been provided with a very long shaft relative to the crown length such that the thread is caused to form several wraps around the shaft. As a result, this easily leads, assisted by hairiness of the thread, to lap formation usually close to and below the thread carrying crown. Furthermore, this thread carrying crown has usually been provided below the thread carrying grooves with a cone which tapers sharply towards the shaft in order to assist lap formation in case of disturbances as the thread is not broken but is further wound onto the lap with the wraps of the cone sloughing off towards the spindle. In addition, once a lap has been started, the continued formation of the lap has been further assisted by the conical tapering of the shaft towards the spindle so that an easy elimination of the lap once the spindle tip extension has been taken off from the shaft is permitted. However, once a lap forms on this tapered cone, the lap slides towards the spindle so that lap formation can continue from the upper part of the spindle tip extension.

In other cases, the spindle tip extension has been provided with a relatively short shaft and with a crown of large diameter which is provided with a sharply tapering cone towards the shaft so that the thread has run along the shaft in a few wraps. However, this sharp cone, in addition to assisting continued formation of a lap once formed for the reasons described above, has been unsuitable for spinning fine counts, as the fine thread has been, e.g., held back too much and has not been easily loosened from the grooves. Thus, the thread has formed many wraps on the shaft which wraps assist in the formations of laps.

Other'spindle tip extensions have also been known which are provided with a long shaft and with a thread carrying crown equipped with a feeble cone and with a few grooves only, the opening angle of each groove being 90 and the base of each forming an angle of to with the spindle axis.

While these known spindle tip extensions reduce the number of wraps, there is the disadvantage that, if e.g., a light traveller is used, the wraps open within a very short time. As a result end breakages occur. Furthermore, due to the large opening angle of the thread carrying grooves, the thread penetrates very deeply into the grooves. Because of this, and also due to the small number of grooves, the thread suffers violent impacts as it is carried on the crown and causes premature wear of ring and traveller. Also, with the known spindle tip extensions provided with a conical shaft of increasing diameter towards the shaft and with a crown the diameter of which exceeds the shaft diameter and with a large number of grooves, which possibly can be shaped so that they exert more grip, an excessive number of wraps are formed and the thread tension becomes too high due to unfavorable ratios of crown diameter to shaft diameter and due to the shapes of the elements.

Attempts have been made with all these known spindle tip extensions to control the wraping of the thread around the shaft and to achieve a reduced balloon by means of a particular selection of the ratios of crown and shaft diameters or of shaft and spindle diameters as well as of the length and the shape of the shaft. It is, however, a common disadvantage of all these known spindle tip extensions, that in the case of a lap formation, the thread is wound loosely onto the conical portion of the crown by the air acting against the rotating spindle, the size of the lap formed depending on the characteristics of the thread. The more tapered the cone is, the more thread is wound onto a lap already formed as the wraps slide from the cone towards the spindle. As the end of such laps are very hard to find once the thread is broken, such laps must be eliminated by means of a sharp tool or by a lifting of the crown from the spindle. This not only is complicated, but, if tools are used, can result in damage to the spindle tip extension. Further, if the spindle tip extension is lifted off, there is the danger that, if the spindle tip extension is carelessly replaced it will be thrown off the spindle during subsequent operation. This necessitates the use of correspondingly more wear resistant and, thus, more expensive, holding means for the spindle tip extension.

Accordingly, it is an object of the invention to pro vide a spindle tip extension for spinning with a reduced balloon which is constructed so that the thread forms a small number of wraps only around the spindle tip extension.

It is another object of the invention to reduce the danger of lap formation owing to the formation of a small number of wraps around a spindle tip extension.

It is another object of the invention to eliminate a lap on a spindle tip extension without lifting the spindle tip 7 extension off the spindle.

Briefly, the invention provides a spindle tip extension for spinning with a reduced balloon with a shaft and a crown having a cone and thread carrying grooves in which there is a mutual coordination of the diameters of the shaft and the crown; the lengths of the shaft and the crown; the cone at the crown and its shape; and the shape of the thread carrying grooves as well as the distance to the thread guide.

The spindle tip extension is mounted by means of the shaft coaxially in the tip of a spindle with the crown being spaced above the spindle and with the cone of the crown tapering off conically towards the spindle. The relative dimensions of the tip extension are such that the shaft diameter is preferably less than a third of the spindle diameter and the ratio of the shaft diameter to the maximum crown diameter is less than 1 to 2.8.

In addition, the length of the shaft as measured between the spindle tip and the transition of the crown cone to the shaft is a half times to three times larger than the shaft diameter while the length of the crown as measured between the maximum crown diameter and the transition of the crown cone to the shaft is one and a half times to four times larger than the length of the shaft. Also, the crown cone forms an angle of 8 to 13 with the axis of rotation of the spindle.

The grooves in the crown are longitudinally oriented with the longitudinal side walls of the grooves sized to form an included angle of less than 70. The length of each groove from the maximum crown diameter to a groove end point on the cone surface is from 3 to 8 millimeters while the bottom of each groove extends towards the top of the crown in the direction of, and forms an angle of preferably less than 30 with the rotation axis of the spindle.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a side view of a spindle with a spindle tip extension according to the invention:

FIG. 2 illustrates a side view of the spindle tip exten-' sion shown in FIG. 1;

FIG. 3 illustrates a top view of the spindle tip extension shown in FIGS. 1 and 2;

FIG. 4 illustrates a side view of another spindle tip extension according to the invention on a spindle tip;

FIGS. 5, 6 and 7 illustrates a side view each of other spindle tip extensions according to the invention;

' FIG. 8 illustrates a schematic side view of a holding device for holding a spindle tip extension in a spindle tip according to the invention; and

FIG. 9 illustrates a cross-sectional view taken along line IX-IX of FIG. 8.

Referring to FIGS. 1 and 2, the tip 1 of a spindle 2 of a diameter A carries a spindle tip extension 3 which extends upwards from the spindle tip 1. The spindle tip extension 3 consists of a shaft 4 of a diameter B fixed in a bore 5 extending coaxially with the rotation axis C of the spindle 2, and of a thread carrying crown 6 of a maximum diameter D. The crown 6 is also provided with a cone 7 which tapers off towards the shaft 4 and extends around the whole circumference as well as with a plurality of longitudinal grooves 8 which are spaced about the whole circumference. The grooves 8 extend as recesses, all of which are of the same depth, radially of the rotation axis C of the spindle 2. For better clarity only a few of the longitudinal grooves 8 are shown in FIG. 2. In addition, the thread carrying crown 6 is provided with a conical cap 9 above the maximum diameter D.

Referring to FIG. 1, during spinning, a thread 10 delivered from above passes through a thread guide 1 l to the thread carrying crown 6, is wrapped around the spindle tip extension 3 and then slides from the spindle tip 1. From the spindle tip 1, the thread 10 forms a balloon 13 down to an antiballoon ring 12 and from there another balloon 16 down to a traveller moving along a ring 14. The thread 10 is subsequently wound onto a tube 17 which is placed onto the spindle 2. The thread shown in broken lines indicates the thread position, e.g., during start-up or after piece-up of an end down,

the thread 10' passing from the thread guide 11 over the thread carrying crown 6 through the anti-balloon ring 12 to the traveller 15, the thread 10 being carried on by the thread carrying crown 6. The anti-balloon ring 12 can be dispensed with if short spindles are used.

Referring to FIG. 2, the diameter B of the shaft 4 is determined by the spindle diameter A and preferably is three and a half to four times smaller than the spindle diameter A. At the diameter D, the thread carrying crown 6 is provided with a cylindrical section 18, the height E of which between an upper edge 19 and a lower edge 20 is less than 2.5 mm and which is ensured by precise maintenance of the diameter D of the thread carrying crown 6. The length F of the thread carrying crown 6, as measured from the upper edge 19 down to a transition point 21 of the cone 7 to the shaft 4, is two and a half to four times than a length G of the shaft 4 effective for the wraps of the thread 10 (FIG. 1) as measured from the spindle tip 1 to the transition point 21. The bottom 22 of each longitudinal groove 8 is shaped in a convex manner withrespect to the axis of rotation C of the spindle 2 and is inclined to the axis of rotation C under an angle of preferably 22 directed towards the top of the extension 3 as viewed. In this respect, as each longitudinal groove 8 is coplanar with the axis of rotation C, the spindle tip extension 3 can be used for opposite directions or rotation.

Referring to FIGS. 2 and 3, the longitudinal grooves 8 are each provided with plain walls and form an opening angle B (FIG. 3) smaller than e.g., 60. The longitudinal grooves 8 can, however, be provided with other wall shapes if needed for better grip, i.e., for better guidance of the thread 10. The longitudinal grooves 8 extend on one side from the maximum diameter D of the crown 6 towards the top and end in the cap 9, and on the other end extend downwardly to the lower groove end 24 on the cone 7. The thread carrying power of the longitudinal grooves 8 is determined not only e.g., by the shape of the walls 23, but preferably also by the length H of each groove bottom 22 as measured from the upper edge 19 down to the groove end 24 on cone 7. For example, in spinning woollen yarns, the length H preferably is long. The length H of each groove bottom 22 thus is in the range of from 3 to 8 mm, depending on the size of the spindle tip extension 3.

The spindle tip extension 3 as shown in FIGS. 1 and 2 is particularly used for spinning coarse yarns, i.e., coarse yarn counts, with a reduced balloon. To this end, the cone 7 of the thread carrying crown 6 tapers off evenly from the maximum diameter D at the lower edge 20 down to the transition point 21 under an angle 'y of from 8 to 13, e.g., 10, relative to the axis of rotation C. The effective length G of the shaft 4 is longer than two thirds and shorter than two and a quarter times the shaft diameter B, and the ratio of the shaft diameter B to the crown diameter D is in a range of less than 1 to 2.75.

The cone 7, as shown on the spindle top extension 3 according to FIGS. 1 and 2, is not suitable for a fine yarn as such a fine yarn may be retained too much on the cone due to the gripping power of the thread carrying grooves 8 such that the fine yarn forms many wraps around the spindle tip extension 3. If the cone 7 forms a very small angle with the axis of rotation C, this would permit achievement of a maximum number of one and a half wraps; however, a very long spindle tip extension would result which would imply the danger that the wraps would loosen up if, e.g., a light traveller is used.

Referring to FIG. 4, wherein like reference characters indicate like parts as above, in order to provide for spinning fine to medium yarn counts or for small to medium size spindles, respectively, a spindle tip extension is provided with a shaft 26 of a diameter K and with a thread carrying crown 27 of a maximum diameter L. The shaft 26 is fixed in a bore 29 extending coaxially with a rotation axis M of a spindle 28 (shown partially only) in the top part 30 of the spindle 28. The thread carrying crown 27 is provided at the maximum diameter L over the whole circumference with longitudinal grooves 31, the groove bottom 32 of which forms a straight line. For better clarity, a few longitudinal grooves 31 only are shown. From the maximum diameter L downwards, the thread carrying crown 27 tapers off first in a slight cone 33 and then in an adjacent more pronounced cone 34 towards the shaft 26. The first cone 33 tapers from the lower edge of the cylindrical section 18 downwardly over a length N to a point below the lower end 24 the grooves 31 and forms an angle '0 with the axis of rotation M of from 3 to 7. The adjoining second cone 34 extends over a length P down to a transition point 35 on shaft 26 to form a angle 5 in the range of from 8 to 13. The shaft length Q as measured from the spindle tip 30 to the transition point 35 is longer than one and smaller then three diameters of the shaft 26 and the ratio of the shaft diameter K to the maximum crown diameter L is less than I 2.5. The total crown length is one and a half to three times longer than the shaft length Q. The construction of the other parts of the spindle tip extension 25 corresponds to the extension 3 shown in FIGS. 1 through 3.

The cone 7 according to FIGS. 1 and 2 and the cones 33 and 34 according to FIG. 4 can alternatively be shaped convex towards the outside, the curvature of the cone 33 in this case being flatter than the curvature of the cone 34.

Referring to FIG. 5, a spindle tip extension 36 can alternatively be provided with a shaft 37 of a diameter R and with a thread carrying crown 38, equipped with a cone 39 which tapers off towards the shaft 37 and has a lower end 40 of a diameter S smaller than the shaft diameter R. In addition, a further cone 4] is provided adjacent to and below the cone 39 and is of a diameter which increases from the same diameter S over a short length T to the shaft diameter R, the cone 41 merging into the shaft 37 thereat. Thus, a recess 42 is formed at the transition from cone 39 to cone 41. The cone 39 is also provided with two circular grooves 43 and 44 which extend over the whole circumference of the spindle tip extension 36. According to the taper angle of the cone 39, one only or more than two circular grooves also may be provided.

During use, should a lap formation occur on cone 39, the yarn (not shown) is continuously wound onto the spindle tip extension 36 and accumulates, preferentially in the lowest groove 43. As a result, the additional yarn which is wound on can no longer slide down towards the shaft 37. After an accumulation has formed in the grooves 43, the further lap formation is also prevented from sliding down towards a spindle (not shown) by the short cone 41, the diameter of which increases towards the spindle. Also, after the groove 43 is filled, the yarn is wound into the groove 44 arranged above the groove 43 and then up to the maximum crown diameter U, where the yarn breaks as it no longer can be wound. Preferably, the yarn is caught in the topmost groove 44, and the rest of the wraps are eliminated overhead.

Referring to FIG. 6, wherein like reference characters indicate like parts as above, instead of using an inversed cone 41 as shown in FIG. 5, a spindle top extension 48 can be provided with a circular groove 47 at a transition 45 of the cone 39 onto a shaft 46.

The thread carrying crown 38 according to FIGS. 5 and 6 respectively includes a conical cap 49 the top 50 of which is rounded off and the conical surface of which includes an angle 4) (FIG. 6) of less than 120. If, during manual or automatic doffing operations, a thread guide 11 (FIG. 11) arranged above the spindle tip extension 3, 36, 48 is tilted away, the traveller 15 and the yarn 13, 16 extending to the traveller 15 from the spindle tip extension 3, 36, 48 can be placed in front of the spindle 2 and can be caught in a groove 8 of the thread carrying crown 6. Loosening of the yarn 13 out of the grooves 8 and shifting of the yarn 13 aside in front of the bobbin 17 before doffing is furthered as, e.g., the hand gripping the bobbin 17 automatically pushes the yarn 13 over the conical cap 49 which automatically permits slipping of the yarn out of the groove 8.

Referring to FIG. 7, instead of using a conical cap 49 the spindle tip extension can be provided with a round cap 51, the radius of which corresponds to the angle shown in FIG. 6' on an otherwise identical tip extension.

Referring to FIG. 8 in order to mount the shaft 52 of a spindle tip extension 53 (shown partially only) in a spindle tip 54 of a spindle 55 (also shown partially only) a bore 56 of a diameter V is provided in the spindle tip 54 and the shaft 52 is e.g., pressed, glued, or secured in another suitable manner in the bore 56 so as to be detachably mounted in the: spindle 55. In addition, a second bore 58 is formed in the portion 57 of the spindle tip 54 to extend coaxially with the bore 56 for a few millimeters. The diameter W of the bore 58 is somewhat larger than the diameter of the bore 56, also, a somewhat larger clearance Z is formed between the circumference of the shaft 52 and the bore 58 than between the shaft 52 and the bore 56. As a result, any individual fibers which penetrate into the clearance Z are thrown out due to the action of the spindle rotation and can not remain trapped as would be the case if the bore 56 extended up to the top surface 57 with the same diameter V.

The invention thus provides a spindle tip extension which can be used for spinning with a reduced balloon using all types of fibers. Further, as the number of wraps on the whole length of the spindle tip extension can be limited to three quarters to one and a half wraps, this permits the spinning of e.g., blends of wool and synthetic fibers or of pure synthetic fibers, in which spinning process laps can easily form if more than one and a half wraps form. Pure wool or cotton is preferentially spun using one and a half wraps or more depending on the type and origin of the material processed. However, in this instance the thread tension e.g., between the delivery rolls and the spindle tip extension, should be lowered to such an extent only that no thread breakages occur in the spinning path.

It is a further advantage of the invention that the distance of the spindle tip extension from a thread guide can be kept small, preferentially from 3 to 6 millimeters. This permits more precise setting of the distance. Furthermore, any laps which form on the spindle tip extension are prevented from increasing in size by the circular groves and/or a recess between the crown cone and the shaft, and the laps which do form can be eliminated easily without removal of the spindle tip extension.

What is claimed is:

1. In combination with a spindle having a tip, a spindle tip extension for spinning with a reduced balloon comprising a shaft mounted in said tip and a thread carrying crown connected to said shaft, said crown having a plurality of circumferentially spaced longitudinal grooves therein and a cone tapering towards said spindle and meeting said shaft at a transition plane, said shaft being of a length effective for wraps of a thread between said tip and said transition plane of longer than a half times and shorter than three times the diameter of said shaft, said crown being of a length between a maximum diameter thereof and said transition plane of from one and a half to four times larger than said shaft length, said maximum diameter of said crown being less than 2.8 times the diameter of said shaft, and said cone forming an angle of from 8 to 13 with respect to the rotational axis of said spindle.

2. The combination as set forth in claim 1 wherein said spindle tip includes a first bore therein receiving said shaft therein and a second bore circumferentially spaced about said shaft and being of a larger diameter than said first bore.

3. The combination as set forth in claim 1 wherein each groove has a bottom extending from said shaft in the direction of said axis of rotation at an angle of less than with respect to said axis of rotation.

4. The combination as set forth in claim 1 wherein said crown has a maximum diameter of less than 2.75 times the diameter of said shaft and wherein said length of said shaft is more than two thirds and less than two and a quarter of said shaft diameter.

5. The combination as set forth in claim 1 wherein said crown has a maximum diameter of less than 2.5 times the diameter of said shaft and wherein said length of said shaft is more than one and less than three shaft diameters.

6. The combination as set forth in claim 1 wherein each groove has a pair of side walls defining an inchided angle of less than 70.

7. The combination as set forth in claim 1 wherein each groove has a bottom extending from a maximum crown diameter to an end point on the surface of said cone over a distance of from 3 to 8 millimeters.

8. The combination as set forth in claim 1 wherein each groove has straight walls.

9. The combination as set forth in claim 1 wherein said crown has a cylindrical section of a height of less than 2.5 millimeters at a maximum diameter thereof as seen from said maximum diameter of said crown in the direction of said shaft.

10. The combination as set forth in claim 1 wherein said cone tapers evenly from a maximum crown diameter to said transition plane.

11. The combination as set forth in claim 1 which further includes a second cone extending from a maximum crown diameter to said cone of said crown and tapers under an angle of from 3 to 7 with respect to said axis of rotation.

12. The combination as set forth in claim 1 which further includes a recess at said transition plane.

13. The combination as set forth in claim 12 which further includes an inverse cone at said transition plane adjacent to said crown cone.

14. The combination as set forth in claim 12 which further includes an annular groove at said transition plane.

15. The combination as set forth in claim 1 which further includes at least one annular groove between a maximum diameter of said crown and said transition plane.

16. The combination as set forth in claim 1 wherein said thread carrying crown has a conical cap with a conical surface of which encloses an angle of less than 120.

17. The combination as set forth in claim 1 wherein said crown includes a round cap.

18. A spindle tip extension for spinning with a reduced balloon comprising a shaft and a thread carrying crown connected to said shaft, said crown having a plurality of circumferentially spaced longitudinal grooves therein and a cone tapering toward and meeting said shaft at a transition plane,

said cone forming an angle of from 8 to 13 with respect to the rotational axis of said shaft;

said crown having a maximum diameter of less than 2.8 times the diameter of said shaft, said shaft being of a length effective for wraps of the threads of longer than a half times and shorter than three times the diameter of said shaft; and

said crown being of a length between said maximum diameter thereof and said transition plane of from one and half times to four times longer than said shaftlength.

19. A spindle tip extension as set forth in claim 18 wherein said crown has a cylindrical section of a height of less than 2.5 millimeters at a maximum diameter thereof as seen from said maximum diameter of said crown in the direction of said shaft.

20. A spindle tip extension as set forth in claim 18 which further includes an inverse cone at said transition plane adjacent to said cone.

21. A spindle tip extension as set forth in claim 18 which further includes an annular groove at said transition plane.

22. A spindle tip extension as set forth in claim 18 wherein each groove forms an included opening edge of less than 23. The combination as set forth in claim 1 which further includes a thread guide spaced above said tip extension a distance of from 3 to 6 millimeters.

24. The combination as set forth in claim 1 wherein said shaft diameter is less than a third of said spindle diameter. 

1. In combination with a spindle having a tip, a spindle tip extension for spinning with a reduced balloon comprising a shaft mounted in said tip and a thread carrying crown connected to said shaft, said crown having a plurality of circumferentially spaced longitudinal grooves therein and a cone tapering towards said spindle and meeting said shaft at a transition plane, said shaft being of a length effective for wraps of a thread between said tip and said transition plane of longer than a half times and shorter than three times the diameter of said shaft, said crown being of a length between a maximum diameter thereof and said transition plane of from one and a half to four times larger than said shaft length, said maximum diameter of said crown being less than 2.8 times the diameter of said shaft, and said cone forming an angle of from 8 to 13* with respect to the rotational axis of said spindle.
 2. The combination as set forth in claim 1 wherein said spindle tip includes a first bore therein receiving said shaft therein and a second bore circumferentially spaced about said shaft and being of a larger diameter than said first bore.
 3. The combination as set forth in claim 1 wherein each groove has a bottom extending from said shaft in the direction of said axis of rotation at an angle of less than 30* with respect to said Axis of rotation.
 4. The combination as set forth in claim 1 wherein said crown has a maximum diameter of less than 2.75 times the diameter of said shaft and wherein said length of said shaft is more than two thirds and less than two and a quarter of said shaft diameter.
 5. The combination as set forth in claim 1 wherein said crown has a maximum diameter of less than 2.5 times the diameter of said shaft and wherein said length of said shaft is more than one and less than three shaft diameters.
 6. The combination as set forth in claim 1 wherein each groove has a pair of side walls defining an included angle of less than 70*.
 7. The combination as set forth in claim 1 wherein each groove has a bottom extending from a maximum crown diameter to an end point on the surface of said cone over a distance of from 3 to 8 millimeters.
 8. The combination as set forth in claim 1 wherein each groove has straight walls.
 9. The combination as set forth in claim 1 wherein said crown has a cylindrical section of a height of less than 2.5 millimeters at a maximum diameter thereof as seen from said maximum diameter of said crown in the direction of said shaft.
 10. The combination as set forth in claim 1 wherein said cone tapers evenly from a maximum crown diameter to said transition plane.
 11. The combination as set forth in claim 1 which further includes a second cone extending from a maximum crown diameter to said cone of said crown and tapers under an angle of from 3 to 7* with respect to said axis of rotation.
 12. The combination as set forth in claim 1 which further includes a recess at said transition plane.
 13. The combination as set forth in claim 12 which further includes an inverse cone at said transition plane adjacent to said crown cone.
 14. The combination as set forth in claim 12 which further includes an annular groove at said transition plane.
 15. The combination as set forth in claim 1 which further includes at least one annular groove between a maximum diameter of said crown and said transition plane.
 16. The combination as set forth in claim 1 wherein said thread carrying crown has a conical cap with a conical surface of which encloses an angle of less than 120*.
 17. The combination as set forth in claim 1 wherein said crown includes a round cap.
 18. A spindle tip extension for spinning with a reduced balloon comprising a shaft and a thread carrying crown connected to said shaft, said crown having a plurality of circumferentially spaced longitudinal grooves therein and a cone tapering toward and meeting said shaft at a transition plane, said cone forming an angle of from 8 to 13* with respect to the rotational axis of said shaft; said crown having a maximum diameter of less than 2.8 times the diameter of said shaft, said shaft being of a length effective for wraps of the threads of longer than a half times and shorter than three times the diameter of said shaft; and said crown being of a length between said maximum diameter thereof and said transition plane of from one and half times to four times longer than said shaft length.
 19. A spindle tip extension as set forth in claim 18 wherein said crown has a cylindrical section of a height of less than 2.5 millimeters at a maximum diameter thereof as seen from said maximum diameter of said crown in the direction of said shaft.
 20. A spindle tip extension as set forth in claim 18 which further includes an inverse cone at said transition plane adjacent to said cone.
 21. A spindle tip extension as set forth in claim 18 which further includes an annular groove at said transition plane.
 22. A spindle tip extension as set forth in claim 18 wherein each groove forms an included opening edge of less than 70*.
 23. The combination as set forth in claim 1 which further includes a thread guide spaced above said tip extension a distance of from 3 to 6 millimeters.
 24. The combination as set forth in claim 1 wherein said shaft diameter is less than a third of said spindle diameter. 